A mobile device such as a cellular telephone typically communicates with a fixed device such as a base station over a portion of radio-frequency (RF) spectrum. For example, the mobile device and fixed device communicate over one or more RF communication channels. In some cases, however, the mobile device may be moving fast enough to cause a frequency shift in the communications frequencies used for the communication channels. Left uncorrected, the frequency shift may degrade communications between the fixed device and mobile device. In an extreme case the frequency shift may cause the communication channel to disconnect or drop entirely. Consequently, there may be a substantial need in compensating for frequency shifts due to mobility issues.